Search
Back to Home Page
Home   |   Contact Us Ph: 443-345-1578

Green Roof Plant Blog

Geranium sanguineum - The Bloody Cranesbill

Green Team at Green Roof Technology, - Tuesday, January 15, 2013

 By: Samantha Yurek


 Photo Credit: Wikipedia

This geranium blooms a bright magenta in the summer, but turns a crimson in the fall, which is where the name Bloody Cranesbill was derived from. A herbaceous perennial with fern-like leaves, this variety of geranium enjoys full sun and well-drained soils with low nutritional value.  Although native to Europe, this plant is far from invasive and makes for great green roof ground cover. The hardiness zones for this plant are 3-8.

This is a green roof plant that can be seeded right now! The geranium is best sowed between November and March.

These plants are easy to expand on your rooftop garden by cloning.  Cloning can be completed in several ways.  Cuttings are a practical and inexpensive way to expand the plant cover on any rooftop garden. 

  • Stem cuttings: in which a piece of stem is part buried in the soil, including at least one leaf node. The cutting is able to produce new roots, usually at the node.
  • Root cuttings: in which a section of root is buried just below the soil surface, and produces new shoots

These cuttings should then be buried in the green roof growing media or spread under a pre-vegetated mat

 Learn more on how to get started with cuttings today!

 

A Cool Green Roof Plants Study

Green Team at Green Roof Technology, - Friday, January 11, 2013

Picture: Greenpeace

By Jorg Breuning

A recent British study in Building and Environment found that broad-leafed plants, such as Stachys byzantina, Bergenia cordifolia and Hedera hibernica, which can thrive in partial shade, outperformed the traditional Sedum in cooling the substrate and surrounding air.  The study concluded by suggesting, “…the choice of plant species on green roofs should not be entirely dictated by what survives on the shallow substrates of extensive systems, but consideration should be given to supporting those species providing the greatest eco-system service potential.”1

This is certainly one of the many worthless studies on the web that shows us that no horticultural understanding or common sense was ever part of the research study.  A green roof is all about the vegetation and if we are not entirely dictated to by what survives, we have simply no plants, no vegetation, and therefore no green roof.  It is also not new that more leaf mass provides cooler temperatures – standing in summer in the forest is cooler than on a corn field.  I always thought this was common knowledge. 

The broad-leafed perennials that were tested (less than 2 year tested) typically require deeper soil profiles.  More green roof growing media (soil) increases the costs of the green roof, the structure and the maintenance dramatically.  Substantially increasing green roof costs decreases the likelihood of having a green roof to start with.  The study also did not mention that the climate conditions in Great Britain are unique and are generously supported with moderate temperatures by the golf stream all year around.  This effect allows higher varieties of plants to start with but won’t guarantee a higher survivability of these plants.

Comparing Sedums with the mentioned type of perennials is like comparing wild strawberries with apples. The survivability of Sedums under extreme conditions on a shallow layer of soil with low nutrients makes them to the ideal, perennial and stabilizing groundcover for extensive green roofs.

There is no doubt that we use other annual or perennial plants as temporary fostering or nursing plants or to promote the growth of Sedums or reduce the pressure of unwanted plants. 

In modern green roof technology there are multiple choices of herbaceous perennial plants that supplement the fundamental Sedum carpet.


Latest Blog Posts
  1. Best Green Roof Solution Green Team at Green Roof Technology, 02-Oct-2017
  2. Health Care and Green Infrastructure Green Team at Green Roof Technology, 01-Jun-2017
Facebook   Twitter   LinkedIn   Google+   YouTube
Go To Resources Page